1) (3x-2)^3+64/27=0
求x。
2) 小明計算√(a+a)時，不小心計算了√a+√a，但結果仍然得出正確答案，問正確答案是多少？
唔該清楚列埋步驟，plz=]
唔該想請教兩條數學題目，想了很久也不懂=[
2013-02-26 5:05 am
回答 (2)
2013-02-26 5:42 am
✔ 最佳答案
1.(3x-2)^3 + 64/27 = 0
(3x-2)^3 = -64/27
(3x-2) = -4/3 (兩邊開三次方)
3x = -4/3 + 2
3x = 2/3
x = 2/9
2.
√(a+a) = √a+√a
a+a = (2√a)^2
2a = 4a
2a = 0
a = 0
如不明白再問
2013-02-27 6:17 pm
HK. has missed an important concept that when taking cubic root, two more complex roots occur, not just only take the real one as the final answer.
Simon YAU.
Simon YAU.
收錄日期: 2021-04-13 19:18:36
原文連結 [永久失效]:
https://hk.answers.yahoo.com/question/index?qid=20130225000051KK00337